Many display signs make no attempt at all to have any kind of flexibility in the mounting of the base, and simply use fixed triangular supports at each outer end of the sign. When some flexibility in the mounting is sought, display signs of this general type are frequently mounted on two large diameter coiled springs secured to a flat bottom member.
A variety of other structures for supporting something such as a display sign have been used over the years. Five prior art patents known to applicant provide means for locking angularly disposed support legs in their open positions, and the last three of these five patents include means for locking the support legs in their closed positions as well. These five U.S. patents are U.S. Pat. No. 2,864,191 issued to Hagen Dec. 16, 1958; U.S. Pat. No. 3,527,434 issued to Mauro Sep. 8, 1970; U.S. Pat. No. 5,028,031 issued to Stoudt Jul. 2, 1991; U.S. Pat. No. 5,040,321 issued to Stoudt Aug. 20, 1991; and U.S. Pat. No. 5,079,861 issued to Stoudt Jan. 14, 1992.
Only two prior art patents are known to applicant in which triangularly disposed support legs are free to fold downward into a closed position when the device is lifted up from the support surface on which it is standing. In both these instances the support legs are kept from moving beyond their support positions by chains or folding links. These two U.S. patents are U.S. Pat. No. 2,900,158 issued to Ditter Aug. 18, 1959 and U.S. Pat. No. 3,219,300 issued to Gunderson Nov. 23, 1965.
U.S. Pat. No. 2,844,897 issued to Vance Jul. 29, 1958 discloses a complicated structure in which the pivot point about which the outwardly extendable legs pivot is slidably enclosable in a boxlike member for transportation of the display sign.
None of these prior art references, which were issued over a long period of time, provides the combination of advantages that is achieved by applicant's invention.